Field of the Invention
The present invention relates to conductive adhesives. More particularly, the present invention is conductive adhesive generally comprising a thermosetting resin, a hardening agent, carbon powder, and carbon fibers, and a method for obtaining and using the same. It is further contemplated that the invention and method of obtaining and using the same are applied in the construction of pipelines where it is desirable to provide a conductive adhesive for reducing or eliminating buildup of dangerous electrostatic charges. 2. Prior Art
Pipelines have long been made from plastics, fiberglass, and other non-metal material. These non-metal pipes and pipelines are often preferred over metal pipelines because they are lighter weight, more corrosive resistant, and often more flexible. By the nature of these materials, theses non-metal pipes and pipelines tend to have a lower electrical conductivity than metal. This, however, is a potential disadvantage in certain applications, uses, and construction.
It is known that as material or fluid passes down a pipeline, static charges are created from friction as the material or fluid passes over the surface of the pipeline. It is not uncommon for these charges to build up to dangerous and damaging levels.
In the transportation of volatile substances via non metal type pipelines, such as associated with the petroleum industry, the discharge of accumulated electrostatic charges can cause catastrophic consequence. Furthermore, it is known that the industry has set standards in the transportation of petroleum products via ships that use fiberglass or plastic piping that such piping must have a surface resistivity of 10*9 ohms so that static charge build-up in the pipe by fluid flow may be conducted to ground. Thus, systems and materials have thus been adapted to reduce electrostatic charges associated with these non metal pipes and pipelines.
In an attempt to reduce the aforementioned hazards, the prior art has added electrically conductive materials to plastic sheets and pipes. For a further discussion of electrically conductive filament-reinforced plastic articles, see Bordner, U.S. Pat. No. 4,330,811 issued May 18, 1982. In Bordner, it is disclosed that pipes and other plastic articles are constructed such that higher electrical conductivity is achieved by adding fiberglass filaments with metal coatings to the articles.
In the construction process of plastic type pipelines, adhesives are used to bond segments of the pipe together. It is known to use conductive adhesives for the purpose of continuing conductivity across bonds in pipeline systems designed to prevent build-up and storage of static electrical charges. For a further discussion of such, see Hajovsky, U.S. Pat. No. 4,874,548 issued Oct. 17, 1989. Hajovsky discloses an electrically conductive adhesive composition comprising an epoxy resin and stainless steel fibers, or other conductive fibers, having a length of about 4 mm to about 8 mm (0.157 inches to 0.315 inches) at a concentration of less than five percent (5%) by weight.
The prior art of conductive adhesives has drawbacks such as but not limited to metal fiber which negatively impacts handling quality when used to formulate joints and fillets. The lack of elasticity of metal fibers in bending or flexing negatively affects the aesthetic and performance quality of the fabricated fillet.
In general, the present invention is a conductive adhesive generally comprising a thermosetting resin, a hardening agent, carbon powder, and carbon fibers generally 13 mm long and with a concentration of generally about eight percent (8%) by weight. It is further contemplated that the method of making such and using are part of the invention.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in this application to the details of construction and to the arrangement of the components set forth in the following description. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
It is, therefore, an object of the present invention to provide a new and improved conductive adhesive and method for obtaining and using the same which continue conductivity across bonds in systems used in pipelines designed to prevent build-up and accumulation of static electrical charges.
It is a further object of the present invention to provide a new and improved conductive adhesive and method for obtaining and using the same which reduces the dangers and hazards associated with electrostatic charges.
An even further object of the present invention is to provide a new and improved conductive adhesive and method for obtaining and using the same which is of a more durable, reliable, and lasting construction than that of the prior art adhesives with conductive properties.
Still another object of the present invention is to provide a new and improved conductive adhesive and method for obtaining and using the same which is susceptible of a low cost of manufacture with regard to both materials and labor, which accordingly is then susceptible of low prices of sale to the consuming industry, thereby making such economically available to the buying public.
Another object of the present invention is to provide a new and improved conductive adhesive and method for obtaining and using the same which provides some of the advantages of the prior art, while simultaneously overcoming some of the disadvantages normally associated therewith.
Yet another object of the present invention is to provide a new and improved conductive adhesive and method for obtaining and using the same which provides a fiber with a high conductivity property in an amount that allows mixing and spreading.
Still yet another object of the present invention is to provide a new and improved conductive adhesive and method for obtaining and using the same which may be easily, efficiently, manufactured, used, and marketed.
It is a further object of the present invention to provide a new and improved conductive adhesive and method for obtaining and using the same which satisfy the consuming industry""s need for an adhesive with functional parameters of such things as conductivity, setting time, and elasticity.
Furthermore, it is also an object of the present invention to provide a new and improved conductive adhesive and method for obtaining and using the same which provides a longer carbon fiber in combination with the carbon powder for assuring consistent high levels of conductivity.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the descriptive matter in which there is illustrated preferred embodiments of the invention.
In accordance with the present invention there is provided a conductive adhesive comprising thermosetting resin and conductive fibers. In general, the present invention is a conductive adhesive generally comprising a thermosetting resin, a hardening agent, carbon powder, and carbon fibers generally 10 to 15 mm and in a preferred embodiment about 13 mm (about 0.5118 inches) long and with a concentration of generally about seven to nine percent and in a preferred embodiment about eight percent (8%) by weight.